virtio-blk: add a knob to disable request merging

this adds a knob to disable request merging for debugging or benchmarks if dedired.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Peter Lieven 2015-02-02 14:52:22 +01:00 committed by Kevin Wolf
parent 95f7142abc
commit c99495ac1b
2 changed files with 5 additions and 1 deletions

View File

@ -531,7 +531,8 @@ void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
/* merge would exceed maximum number of requests or IO direction
* changes */
if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS ||
is_write != mrb->is_write)) {
is_write != mrb->is_write ||
!req->dev->conf.request_merging)) {
virtio_blk_submit_multireq(req->dev->blk, mrb);
}
@ -950,6 +951,8 @@ static Property virtio_blk_properties[] = {
#ifdef __linux__
DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, true),
#endif
DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0,
true),
DEFINE_PROP_BIT("x-data-plane", VirtIOBlock, conf.data_plane, 0, false),
DEFINE_PROP_END_OF_LIST(),
};

View File

@ -113,6 +113,7 @@ struct VirtIOBlkConf
uint32_t scsi;
uint32_t config_wce;
uint32_t data_plane;
uint32_t request_merging;
};
struct VirtIOBlockDataPlane;